Sikkim is rich in avifauna and is considered to be a birdwatchers paradise. Its avian population extends to almost 550 species. The climate varies between the tropical heat of the valleys and the alpine cold of the snowy regions. The altitudinal zones of vegetation range from tropical, sub tropical, temperate to Alpine. The telescoping of terrain has created marked altitudinal zonation in the humidity, rainfall, climate and vegetation. This factor is responsible for the great variety and abundance of the resident bird life, making this area arguably one of the richest areas of its size anywhere in the world.
Over the years Sikkim has become the most favored location for birders all over world. Sikkim is like a small piece of land surrounded on all sides by mountain walls. Within an area of 80kms, the elevation rises from 225 mtrs in Teesta river valley to 8600 mtrs at Khanchendzonga, India highest & World's third highest mountain peak. Separated by Singalila Range from Nepal in the west & Dongkya Range from Tibet to the east, Sikkim, is like a "bird catchment area." Nowhere in the world in such a small area can one find flora and fauna of all varieties - Tropical to the Alpines.